The present invention relates to electrical component housing structures and methods for their manufacture.
Flexible foil carrier housing assemblies are well-known. These assemblies comprise a foil and a carrier housing. Electrical components, which can be resistors, capacitors, coils, transistors or the like, as well as electrical contact elements which can be mechanical, electrical or magnetic switches, contact pins or the like, are arranged on the foil and are electrically connected to conductive tracks of the foil.
It is known from prior art to provide carrier structures which shape flexible conductor foils in space and which keep said foils in that shape. For example, an interaction between carrier structures and foils of this type is described in the German laid-open document DE 44 36 523 A1 and DE 199 40 339 A1. The carrier structures according to those documents are manufactured by injection molding around the foils with a molding mass forming said carrier structure. The shape determined for the carrier structure during the injection molding determines the shape of the foil in space. Changing the shape of the foil after the carrier structure is injection molded is disadvantageously not possible.
Methods of manufacturing a foil carrier housing assembly are known from prior art.
For example, the German laid-open document DE 44 36 523 A1 shows a method for manufacturing a foil carrier housing assembly wherein at first in a first method step, a foil provided with electrical components and contact elements is partially injection molded with a molding mass, such that recesses corresponding to the component housings remain in the region of the components and the contact elements, wherein subsequently in a second method step, the foil is provided with components and/or contact elements through the recesses, and wherein finally in a third method step, the partially injection molded foil is once again injection molded with said injection molding mass whereby a carrier housing is manufactured.
The German laid-open document DE 199 40 339 A1, in turn, discloses a method for manufacturing a foil carrier housing assembly wherein the foil is injection molded with an injection molding mass within a molding tool, such that a carrier housing in the form of a lattice-like or net-like plastic casing is produced.
The methods of the above mentioned documents have in common that it is not possible to replace the foil or the electrical element in foil carrier housing assemblies manufactured according to them, which is for example necessary in the case of a defect of the foil or the component.
The present invention provides a carrier structure comprising at least two portions, each portion being provided with at least one securing mechanism, such that the securing mechanisms can engage each other for generating a fixed spatial arrangement of said portions with respect to each other. In contrast to prior art, the carrier structure according to the invention is not fixed in its form after its manufacture, but can modify its shape by modifying the spatial arrangement of the portions with respect to each other. The respective arrangement of the portions with respect to each other is fixed by means of a securing mechanism. Since the carrier structure holds the foil and since thus each portion of the carrier structure likewise holds a part of the foil, the modification of the spatial arrangement of the portions with respect to each other involves a shaping of the flexible foil in space. Thereby, the shape of the foil in space can be modified also after the manufacture of the carrier housing.
There are different exemplary embodiments of the carrier structure. One exemplary embodiment of the carrier structure which is realized as a carrier lattice comprising enclosing frames and transversal bridges, is especially advantageous. The lattice-like or net-like structure advantageously material-saving. Furthermore, said structure provides also after the manufacture of the carrier structure portions of the foil between the enclosing frames and the transversal bridges which are accessible from outside. Thereby, also after the manufacture of the carrier structure, for example electrical components or the like can be placed on the surface of the foil.
Likewise, there are different exemplary embodiments for the securing mechanisms. For example one of mechanisms can be realized as plug-in pin and the other as plug-in socket. In this case, generating a fixed spatial arrangement between the portions of the carrier structure with respect to each other corresponds to introducing the plug-in pins into the plug-in sockets. The plug-in pins are frictionally engaged within the plug-in sockets. Therefore, the engagement between plug-in pin and the plug-in socket is removable by pulling the plug-in pin out of the plug-in socket. In case a permanent fixing of the plug-in pin within the plug-in socket has to be secured, the plug-in pin can for example be glued in the plug-in socket.
The carrier structure can hold the foil in several ways. One exemplary embodiment of the carrier structure comprises holding pins and holding openings for that purpose. The holding pins of the carrier structure and the holding openings of the foil are assigned to each other in number and arrangement. In this exemplary embodiment, the carrier structure holds the foil in that the holding pins penetrate the holding openings. In order to guarantee a fixed holding of foil by the carrier structure, the heads of the holding pins can be deformed. Moreover, the holding of the foil by the carrier structure can be realized in that the foil is glued onto the carrier structure. Likewise it is possible to manufacture the carrier structure by injection molding or casting around the foil with a molding mass. In this case, the holding of the foil by the carrier structure is effected such that the molding mass adheres to the foil. Preferably, the molding mass is plastic. As far as manufacturing methods are concerned, it is advantageous if the securing mechanisms are manufactured with the manufacture of the carrier structure since in this case, the carrier structure and the securing mechanism are manufactured in one step. After the manufacture of the carrier structure by injection molding or casting, the portions of the carrier structure are moveable with respect to each other and, so to say, kept together only by the foil. In case the portions are moved with respect to each other unintendedly, a damage to the foil in the region between the two portions of the carrier structure can result. In order to avoid this, one exemplary embodiment of the invention provides breakable bridges which connect the portions of the carrier structure. The breakable bridges prevent an unintended movement of the portions with respect to each other. They may be removed before the foil is shaped in space.
The foil can be provided with a plurality of electrical components and/or electrical contact elements. For example the electrical components are resistors, capacitors, coils, transistors or the like, and the electrical contact elements can be mechanical, electrical or magnetic switches, contact pins and the like.
Handling the manufacture of the carrier structure is especially easy if the carrier structure is plane before the foil is shaped in space. This means, that the enclosing frames, the transversal bridges and, if present, the breakable bridges of the carrier structure as well as the foil extend in a plane.
One aspect of the invention provides a method for manufacturing a component carrier structure comprising the steps of: manufacturing the carrier structure and securing mechanisms by injection molding or casting around a foil, and generating an engagement between the securing mechanisms. Thus, by adding to step of manufacturing the carrier structure by injection molding or casting around the foil one additional method step of manufacturing an engagement between the securing mechanisms, modifying the spatial arrangement of the portions of the carrier structure with respect to each other for shaping the foil in space is possible also after a carrier structure is manufactured.
In case that the two portions of the carrier structure are connected by breakable bridges, the latter may be removed before the foil is shaped in space.
In one exemplary embodiment of the method, a further step is performed which comprises the manufacture of a carrier housing by injection molding or casting the carrier structure with a molding mass. In this case, the carrier structure represents an intermediary tool maintaining the shape of a foil in space for manufacturing the carrier housing. After the carrier housing is manufactured, the carrier structure is a part of the carrier housing; in particular if the carrier structure and the carrier housing are manufactured using the same molding mass, the carrier housing and the carrier structure cannot be distinguished from each other.
It is possible, to provide the foil with electrical components and/or electrical contact elements at various points in the manufacture process.
According to a second aspect of the invention, there is provided a method for manufacturing an electrical component housing assembly including a flexible foil incorporating a plurality of conductive tracks, said conductive tracks being selectively electrically connected to respective contact elements and at least one electrical component located within a component housing, said method comprising the steps of: [1a] mechanically and electrically connecting the foil to the electrical component and the electrical contact element, [1b] manufacturing at least one open component housing around at least one of the electrical components by injection molding or casting, [1c] sealing the open component housings by injection molding or casting, and [1d] mechanically connecting the sealed component housings to the carrier housing. In contrast to the prior art methods, mechanically connecting at least one part of the foil and the carrier housing is provided as a last step in the method according to the invention. Preferably, the connection between the foil and the carrier housing enables a quick replacement of the foil and/or the electrical component.
In step [1a], the electrical components and the contact elements can be connected to the foil in several ways. The more important of these ways are soldering or welding, particularly laser welding.
In step [1c], sealing the component housings can be performed, such that the components contained in the component housings are totally covered by injection molding mass. In this case, the component is completely encapsulated and therefore optimally protected from harmful external influences. Additionally, sealing the component housings in step [1c] can be performed, such that the components contained in the component housings are nearly partially covered by the injection molding mass which is for example advantageous when the component comprises connection portions to which further electrical components are connected to later or if the component is to be trimmed later. In this case, the component housings can also be completely sealed during a further step performed after step [1d]. 
Furthermore, there is provided a second method for manufacturing an electrical component housing assembly including a flexible foil incorporating a plurality of conductive tracks, said conductive tracks being selectively electrically connected to respective contact elements and at least one electrical component located within a component housing, said method comprising the steps of: [2a] manufacturing a component housing, [2b] manufacturing the component housing by injection molding or casting contact element, and [2c] mechanically and electrically connecting the foil, the component housing and the carrier housing. This method according to the invention is likewise distinguished from prior art by mechanically connecting a foil and the carrier housing as a last step. According to the above explanations, the second method enables a quick replacement of the foil and/or the electrical components, as well.
There is also provided a still further method of manufacturing an electrical component housing assembly including a flexible foil incorporating a plurality of conductive tracks, said conductive tracks being selectively electrically connected to respective contact elements and at least one electrical component located within a component housing, said method comprising the steps of: [3a] manufacturing component housings, [3b] manufacturing the carrier housing by reverse side injection molding or casting the foil and [3c] mechanically and electrically connecting the carrier housing, the contact elements and the component housings. In accordance with the two methods already explained, this method likewise provides mechanically connecting as a last step whereby also in this case, a quick replacement of the foil and/or the electrical component is enabled.
As far as manufacturing the component housings in step [2a] or [3a] is concerned, a method is especially preferred which comprises the following steps: [A] manufacturing a punched lattice comprising a plurality of structurally identical portions by punching a sheet consisting of electrically conductive material, or providing a circuit board having a plurality of structurally identical portions, [B] manufacturing open component housings by injection molding or casting each of the structurally identical portions, [C] mechanically and electrically connecting the open component housings to the electrical components by soldering or welding, preferably laser welding, the components within the component housings, such that the electrical component are conductively connected to the punched lattice or the circuit board, [D] sealing the component housings by injection molding or casting the component housings, and [E] separating the component housings by cutting the punched lattice or the circuit board. By using this method, a great number of component housings can quickly and easily be manufactured.
Step [2c] or [3c] proving mechanically and electrically connecting can be realized in different ways. For example, the foil can have in the region of the conductive tracks openings, and the component housings can have pin like punched lattice connecting portions assigned in number and arrangement to said openings. In this case, mechanically and electrically connecting in step [2c] or [3c] means introducing the punched lattice connecting portions into the openings, generating a contact between the punched lattice connecting portions and the conductive tracks and, if necessary, soldering or welding (laser welding) the punched lattice connecting portions to the conductive tracks.
Mechanically connecting according to step [1d], [2c] or [3c] can be realized in different ways. For example, the carrier housing can have a recess the cross section of which corresponds to the shape of foil. In this case, mechanically connecting according to step [1d], [2c] or [3c] corresponds to introducing the foil into the recess. Alternatively or additionally, the carrier housing can have connecting protrusions, and the foil can have connecting openings assigned in number and arrangement to the connecting protrusions. In this case, mechanically connecting according to step [1d], [2c] or [3c] means introducing the connecting protrusions into the connecting openings respectively assigned and subsequent pressure deforming the connecting protrusions. Alternatively or additionally, the carrier housing can have connecting pockets having receiving grooves, and the component housings can have engaging edges assigned in number and arrangement to the receiving grooves. In this case, mechanically connecting according to step [1d], [2c] or [3c] means introducing the engaging edges into the receiving grooves until the component housings are completely received within the connecting pockets.
A preferred embodiment of the method provides that the conductive tracks of the foil are copper tracks.
Preferably, the component housings and a carrier housing are made of plastic.